Parabiotic rats had a twelve inch segment of the rat's intestines exchanged for that of its partner. In this preparation, the food that one rat eats travels to its own stomach, through the upper half of its own duodenum into the lower duodenum of its partner. The food travels through 12 inches of the partner's intestines and then returns to the rat that fed. In this preparation, half of the food eaten is absorbed into each rat. The crossing of the intestines has no effect upon feeding behavior when one rat is fed 30 or 60 minutes before the other. Nutrients absorbed from or hormones released by the crossed intestinal segment do not affect food intake. The studies in this research grant extend these findings to longer periods of time during which only one rat of each pair is fed. The present studies also investigate the location and chemical nature of satiety signals that must arise in the stomach or upper duodenum of the rat.